Not necessarily. Orlando never had a 7 footer when they went to the Finals (In '09, not '95). Shit they didn't even have a PF either.

Height has nothing to do with it, it's play style. Dwight is a Center in every sense of the word. Bosh is about as far away as you can get on the big man spectrum. There's a reason they've been getting killed on the glass. It's not about "height", it's about the mentality and skillsets of your players.